Light detection and ranging (LIDAR) indicates detecting a target and measuring a distance to the target using light. The LIDAR is similar in function to radio detection and ranging (RADAR), but is different from the RADAR using a radio wave in that it uses the light. For this reason, the LIDAR is also called ‘image RADAR’. Due to a Doppler effect difference between the light and a microwave, the LIDAR has bearing resolution, range resolution, and the like, more excellent than those of the RADAR.
As a LIDAR apparatus, an airborne LIDAR apparatus of emitting a laser pulse in a satellite or an aircraft and receiving a pulse back-scattered by particles in the atmosphere in a ground observation post has been mainly used. The airborne LIDAR apparatus has been used to measure existence and movement of dust, smoke, aerosol, cloud particles, and the like, together with wind information and analyze distribution of dust particles in the atmosphere or a degree of air pollution. Meanwhile, recently, a terrestrial LIDAR apparatus serving to detect an obstacle, model a terrain, and obtain a position up to a target by installing both of a transmitting system and a receiving system on the ground has been actively studied in consideration of application to a national defense field such as a surveillance patrol robot, a battle robot, an unmanned surface vehicle, an unmanned helicopter, or the like, or a civilian field such as a civilian mobile robot, a smart vehicle, an unmanned vehicle, or the like.
The terrestrial LIDAR apparatus is generally configured to include a transmitting optical system emitting a laser pulse, a receiving optical system receiving reflected light reflected by an external object, and an analyzing unit determining a position of the object. Here, the analyzing unit determines a time required for transmission and reception of the reflected light to calculate a distance up to the object reflecting the light, and calculate distances with respect to reflected light received particularly in each direction, thereby making it possible to create a distance map within an image corresponding to a field of view (FOV).
However, since the terrestrial LIDAR apparatus according to the related art emits laser of which a beam width corresponding to the field of view is wide and obtains the reflected light simultaneously in all directions within the field of view to obtain a distance up to a reflector, the terrestrial LIDAR apparatus according to the related art requires a laser module having a very high output, such that a cost thereof is very expensive. In addition, the laser module having the high output has a large size, which causes an increase in an entire size of the LIDAR apparatus.
Particularly, a LADAR apparatus having a panoramic scanning function includes a transmitting optical system and a receiving optical system, such that the entire apparatus is rotated and operated. Examples of this apparatus have been disclosed in U.S. Patent Application Publication Nos. 2011/0216304, 2012/0170029, and 2014/0293263, and U.S. Pat. No. 8,836,922. However, in the case of rotating the entire apparatus as described above, a size of a system is further increased, which is not good in terms of aesthetics and further intensifies an increase in a cost and power consumption.